1. Field of the Invention
The present invention relates to an ambulatory aid, especially to an ambulatory aid having a tight and firm structure for preventing instability and providing high safety.
2. Description of Related Art
Refer to FIG. 9, this is a walking stick for old people who have low-level moving activity due to poor physical function or people with wounded legs. The walking stick mainly includes a hollow main rod 6 and a support pole 7. A cushion unit 8 is arranged between the main rod 6 and the support pole 7. The cushion unit 8 consists of a sleeve 81, an assembly rod 82, an elastic body 83 and a support block 84. One end of the assembly rod 82 is connected to and fixed on the one end of the support pole 8 and the elastic body 83 is placed around the assembly rod 82 while the other end of the assembly rod 82 disposed with the support block 84 is mounted into a hollow part of the sleeve 81. Due to the support block 84, the sleeve 81 with grooves 811 around a wall thereof is forced to expand. By the expanded sleeve 81 assembled into a hollow part of the main rod 6, the main rod 6, the support pole 7 and the cushion unit 8 comprise the walking stick.
However, in the walking stick, the cushion unit 8 and the main rod 6 are connected and fixed with each other mainly by friction between the expanded sleeve 81 and an inner wall of the hollow part of the main rod 6. When the users press the walking stick downward with a larger pressure or a ground reaction force is lager than the friction between the sleeve 81 and the inner wall of the main rod 6, the connection between the cushion unit 8 and the main rod 6 has come loose, cushion unit 8 is retracted and the walking stick is getting shorter. The user easily falls down.